A display device, for example, a liquid crystal display panel used for a liquid crystal display device, includes a TFT substrate, a counter substrate facing the TFT substrate, and a liquid crystal sandwiched between the TFT substrate and the counter substrate. In the TFT substrate, pixels having pixel electrodes, thin film transistors (TFT) and the like are arranged in a matrix. In the counter substrate, color filters and the like are formed at locations corresponding to the pixel electrodes of the TFT substrate. In this way, the liquid crystal display device forms an image by controlling the transmittance of light of the liquid crystal molecules for each pixel.
Liquid crystal display devices are flat and lightweight and extensively used is growing in a variety of applications. Compact liquid crystal display devices are widely used in electronic devices such as mobile phones and digital still cameras (DSC). The viewing angle characteristics are important for the liquid crystal display device. The viewing angle characteristic is the phenomenon in which the brightness changes or the color changes between when the display is viewed from the front and when the display is viewed from an oblique direction. The viewing angle characteristics are excellent in the in-plane switching (IPS) mode in which liquid crystal molecules are moved by the electric filed in the horizontal direction.
There are many different types of the IPS mode. For example, a common electrode is formed flat, on which a pixel electrode having a slit is provided with an insulating film interposed therebetween, to rotate liquid crystal molecules by the electric field generated between the pixel electrode and the common electrode. This type can increase the light transmittance and is becoming mainstream. There is a structure in which an organic passivation film is provided between the pixel electrode and common electrode and the TFT substrate. However, in order to simplify the manufacturing process, a structure in which the organic passivation film is not provided is also becoming popular.
In the liquid crystal display device, the distance between the TFT substrate and the counter substrate, namely, the thickness of the liquid crystal layer has a significant influence on the characteristics. In general, the liquid crystal display device has been configured such that the distance in the display area is maintained by a cylindrical spacer, and that the distance in a sealing portion is maintained by a glass fiber. In recent years, however, in order to reduce the width of the so-called frame of the liquid crystal display panel, the leaders of scan lines or image signal lines are formed on the lower side of the sealing portion by double metal layer technology. In this case, the glass fiber is hard, so that there is a risk that the scan line leaders or image signal line leaders will be destroyed in gap adjustment. In order to prevent this, JP-A No. 168878/2009 describes the use of a cylindrical spacer formed by a resin also in the sealing portion.
Further, JP-A No. 168878/2009 also describes a method for providing an organic passivation film as a mount for the cylindrical spacer in the sealing portion or in the vicinity thereof, in order to adjust the distance between the TFT substrate and the counter substrate in the display area.
In the third embodiment of JP-A No. 168878/2009 there is described a liquid crystal display device in which the organic passivation film is not present. Also in this case, the distance between the TFT substrate and the counter substrate in the sealing portion is provided by the cylindrical spacer without using the glass fiber. Further, there is also proposed a structure for forming cylindrical spacers both inside and outside the sealing portion. In JP-A No. 168878/2009, however, there is no description of a method for providing the distance by the cylindrical spacers in the display area and in the vicinity of the sealing portion when the organic passivation film is not used.